Reversing too much sharpening

[bill t.]

I think Minor White once said "the light can kill."  Well, I got suckered into printing a shot where the sharpening can kill.  It's so bad it hurts the eyes, and no other version of the image is available.

So what's the state for reversing too much post-processing sharpening?

A little gaussian blur seems to help, but in this day of fancy image-processing algorithms is there a more elegant cure for an image where somebody has put the pedal to the metal in Unsharp Mask?

Would appreciate your suggestions.

[Mark D Segal]

I think Minor White once said "the light can kill."  Well, I got suckered into printing a shot where the sharpening can kill.  It's so bad it hurts the eyes, and no other version of the image is available.

So what's the state for reversing too much post-processing sharpening?

A little gaussian blur seems to help, but in this day of fancy image-processing algorithms is there a more elegant cure for an image where somebody has put the pedal to the metal in Unsharp Mask?

Would appreciate your suggestions.

You may not like to hear this, but for future reference, ALWAYS make these things reversible. Sharpen on separate layers and keep them. You can institutionalize this practice by buying Photokit Sharpener 2.0. You will never have this problem again. It also has some smoothing functions in the Creative Sharpener set which may help to mitigate the issue you now have. You can download a demo (www.pixelgenius.com) and give it a whirl. It's the best thing that happened to digital imaging software aside from Photoshop itself. Another thing you can do, if it is TIFF, PSD or JPEG is open the image in Camera Raw or Lightroom, and use their sharpening tools to de-sharpen, so to speak (sliding in the softening direction.

[Bart_van_der_Wolf]

So what's the state for reversing too much post-processing sharpening?

A little gaussian blur seems to help, but in this day of fancy image-processing algorithms is there a more elegant cure for an image where somebody has put the pedal to the metal in Unsharp Mask?

Hi Bill,

If the method of sharpening used is known, it might help a bit to reverse it's effect with a convolution. When the over-sharpening is that strong, a better approximation of the sharpening function is required. There probably is also a lot of irreversible data loss involved.

Cheers,
Bart 

[bill t.]

Thanks Mark, I'll give it a go in Lightroom and it's probably time to take another look at Photokit Sharpener.  I couldn't get the demo to run on my Vista system several versions ago, but it looks like there have been plenty of new versions since then.

I'm afraid subtleties like layers and non-destructive editing and preserving the camera file were outside the orbit of the original photographer.  Things like this serve to remind to never, never volunteer.  And this also gives me a special compassion for those involved in custom printing.

[Mark D Segal]

Uhuh, I hear ya. Seriously - do try the demo of PKS 2.0. It should install on your computer. If it doesn't, send them an email and ask for help. Once you start using this you will never go back.

[bill t.]

Thank you Bartvander for calling my attention to convolution filters.  I wonder what sort of parameters would be needed for Unsharp Mask, which I assume is a type of convolution filter.

Anyway, got a not-horrible print on schedule by stacking up three layers of the image with varying degrees of gaussian blur, then picking off bits of the least awful areas with masks.  It's sort of graphic looking, but OK for the purpose.

This must come up often in custom printing work, curious how we don't see a lot of specialized processing products pitched to those guys who must face problems like these all the time.

[Schewe]

In the future I would do a merged layer above and try doing .2 Gblur 5 or six times in a row. The key is to use a super low radius multiple times. I outline this in the Real World Image Sharpening book.

If the sharpening artifacts are producing too much light contour you can try setting the blending to darken only.

If the overall over sharpening is really just hitting the edges too much, you might also try creating an edge mask using Find Edges on a copy of the Green channel (or do a luminosity based selection by command/clicking on the RGB image icon). You'll need to modify the tonality a bit and run Gblur on the mask. Try to get the mask so it's only showing the slight edges and you can concentrate the image Gblur to just the edges...

 

[Bart_van_der_Wolf]

Thank you Bartvander for calling my attention to convolution filters.  I wonder what sort of parameters would be needed for Unsharp Mask, which I assume is a type of convolution filter.

Hi Bill,

Well, without better knowledge of the method that was used for the sharpening, you might try an inverse High-pass layer. In Photoshop, make a duplicate layer, perhaps desaturate it, and invert it. Change the blending mode to something like Softlight, and play with the Radius of the High-pass filter.

If one layer doesn't do the trick then use several inverted HP layers, with different radius settings if needed, and adjust the opacity when needed.

Cheers,
Bart

[mediumcool]

Keep your RAWs untrammelled!

[RFPhotography]

Use Smart Objects.  Doing so makes Sharpening a Smart Filter.  Entirely editable and reversible.  For the future, of course.